The present invention relates to stabilized lithium metal powder (“SLMP”) having better stability and a longer storage life. Such improved SLMP can be used in a wide variety of applications including organo-metal and polymer synthesis, rechargeable lithium batteries, and rechargeable lithium ion batteries. One area of interest is the use of rechargeable lithium and lithium ion batteries in electronic applications such as in cellular phones, camcorders, and laptop computers, and even more recently, in larger power applications such as in electric vehicles and hybrid electric vehicles. In these applications it is desirable that the secondary batteries have the highest specific capacity possible but still provide safe operating conditions and good cycleability so that the high specific capacity is maintained in subsequent recharging and discharging cycles.
Although there are various constructions for rechargeable lithium batteries, each construction includes a positive electrode (or cathode), a negative electrode (or anode), a separator that separates the cathode and anode, and an electrolyte in electrochemical communication with the cathode and anode. For secondary lithium batteries, lithium ions are transferred from the anode to the cathode through the electrolyte when the secondary battery is being discharged, i.e., used for its specific application. During this process, electrons are collected from the anode and pass to the cathode through an external circuit. When the secondary battery is being charged or recharged, the lithium ions are transferred from the cathode to the anode through the electrolyte.
Historically, secondary lithium batteries were produced using non-lithiated compounds having high specific capacities such as TiS2, MoS2, MnO2 and V2 O5, as the cathode active materials. These cathode active materials were coupled with a lithium metal anode. When the secondary battery was discharged, lithium ions were transferred from the lithium metal anode to the cathode through the electrolyte. Unfortunately, upon cycling, the lithium metal developed dendrites that ultimately caused unsafe conditions in the battery. As a result, the production of these types of secondary batteries was stopped in the early 1990's in favor of lithium-ion batteries.
It is known to stabilize the lithium powder, particularly for its use in secondary batteries. For example, lithium powder can be stabilized by passivating the metal powder surface with CO2 such as described in U.S. Pat. Nos. 5,567,474, 5,776,369, and 5,976,403, the disclosures of which are incorporated herein in their entireties by reference. The CO2 passivated lithium metal powder, however, can be used only in air with low moisture levels for a limited period of time before the lithium metal content decays because of the reaction of the lithium metal and air. Thus there remains a need for stable lithium metal with an improved storage life.